Hello,
May I know if this problem occur suddenly after the Android Remote Desktop client is upgraded to a new version?
Please recheck the configuration of the RDP file after the client is updated. In addition to the URI call application using the Remote Desktop Protocol you mentioned, please try to log in directly in the Android Microsoft Remote Desktop using the full remote PC name or IP, as well as the full Windows username and password.
In addition, please make sure that your device and remote PC are connected to the network normally and the network connection is stable. You can use the ping command on the Remote Desktop (RD) PC to test the network connection to the mobile phone.
References:
Get started with the Android client | Microsoft Learn
Remote Desktop URI scheme | Microsoft Learn
I hope this helps.
Best regards